This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 4 |
| 6 | 22 |
| 7 | 107 |
| 8 | 486 |
| 9 | 2075 |
| 10 | 8548 |
| 11 | 33851 |
| 12 | 130365 |
| 13 | 489387 |
| 14 | 1799700 |
| 15 | 6499706 |
| 16 | 23118465 |
| 17 | 81134475 |
| 18 | 281454170 |
| 19 | 966388692 |
| 20 | 3288208176 |
| 21 | 11098235911 |
| 22 | 37188198356 |
| 23 | 123800999503 |
| 24 | 409715126169 |
| 25 | 1348690034859 |
| 26 | 4417932007626 |
| 27 | 14407260221164 |